The Council of Aragon, officially, the Royal and Supreme Council of Aragon (Spanish: Real y Supremo Consejo de Aragón; Aragonese: Consello d'Aragón; Catalan: Consell Suprem d'Aragó), was a ruling body and key part of the domestic government of the Spanish Empire in Europe, second only to the monarch himself. It administered the Crown of Aragon, which was composed of the Kingdom of Aragon, Principality of Catalonia (including Roussillon until 1659), Kingdom of Valencia, Kingdom of Majorca, and finally the Kingdom of Sardinia. The Aragonese possessions in Southern Italy (Naples and Sicily) were later incorporated into the Council of Italy, together with the Duchy of Milan, in 1556. The Council of Aragon ruled these territories as a part of Spain, and later the Iberian Union.[1][2]